This invention relates to window panes for motor vehicles having a molded-on edge part with an adhesive application surface for the application of an adhesive to connect the edge part to a mounting flange in a window opening for the motor vehicle in which the connection between the edge part and the fastening flange is releasable by exerting a pushing or pulling force on the window pane. The invention furthermore relates to a motor vehicle having at least one such window pane, to an adhesive application profile for such a window pane, and to a method of producing such a window pane.
Motor vehicle window pane mounting arrangements of the foregoing type are disclosed in German Offenlegugsschrift No. 43 01 026 and European Published Application No. 0 620 134. In those publications, an adhesive application surface is provided on the arms and the yoke of a portion of the edge part which is U-shaped or pinetree-shaped in cross section. That portion is in the form of a polymer profile in which the arms have undercuts serving as anchoring projections for a bead of adhesive introduced into the space between the arms and the yoke. The releasability of the connection between the frame-like edge part of the window pane and the fastening flange is achieved in the disclosed arrangements because the bead of adhesive and the polymer profile do not become adhesively bonded, so that, after hardening, the bead of adhesive is engaged in a positive-locking manner with the polymer profile, with the arms meshing, but is not bonded thereto. Under pressure applied to the window pane from the inside, the arms of the polymer profile bend elastically outwardly and thus separate from the hardened bead of adhesive so that the window pane can readily be removed from the window opening.
These window panes, mounted according to the so-called pop-out principle, have the advantage that they are not only easy to remove, but can also be inserted again later without reworking.
However, the conventional pop-out window panes have some disadvantages. Since the entire space between the arms of the edge part has to be filled with adhesive, the consumption of adhesive is relatively high which, on the one hand, slows down the working process and, on the other hand, reduces the availability of the adhesive application device because the replenishment of the adhesive supplied in drums is often interrupted. Moreover, the nozzle of the adhesive application unit must be inserted into the space between the arms of the U-shaped profile, which likewise slows down the working process somewhat and necessitates the use of a reduced nozzle diameter. This makes it difficult or impossible to mix the installation of panes having the said U-shaped profile and conventional panes in which a wedge-shape ramp of adhesive has to be applied directly to the glass or to a spacer. Additionally, in the case of a smaller nozzle diameter, the pressure in the adhesive application unit must be higher, which results in greater wear.
Since the adhesive is surrounded after application by the U-shaped profile, no air moisture, which is necessary for the adhesive to harden, reaches the adhesive. For this reason, in the conventional window pane fastening arrangements, hydroxyl ions or a wet curing solution have to be applied to the inner side of the U-shaped profile, as described in European Published Application No. 0 620 134, to accelerate curing and thereby avoid the necessity for providing large parking areas at the motor vehicle manufacturers' on which the otherwise finished motor vehicles would have to be parked until the adhesive hardens. Additionally, in the event of high demand, substantial losses of income will also be caused due to the delay in supplying the parked vehicles. Furthermore, since the adhesive and the edge part of the window pane must not become adhesively bonded, only very specific material pairings can be used, which are not always optimally suited with respect to other properties, such as extrusion capacity, material costs, etc.